1. Technical Field
This disclosure relates generally to an organic light emitting display apparatus, and more particularly, to an organic light emitting display apparatus that resists deterioration of organic emission layers from contact with impurities such as oxygen and moisture.
2. Description of the Related Art
Organic light emitting display apparatuses have emission layers formed of organic substances disposed between a pixel electrode and an opposite electrode. In embodiments of organic light emitting display apparatuses, when positive and negative voltages are applied to the electrodes, holes injected from the pixel electrode move into a emission layer through a hole transport layer, and electrons injected from the opposite electrode move to the emission layer through an electron transport layer. The electrons and holes combine, forming excitons in the emission layer. As the excitons relax from an excited state to a ground state, they transfer energy to phosphor molecules in the emission layer, causing the phosphor molecules to emit light, thereby forming images.
Embodiments of organic light emitting apparatuses are regarded as next-generation display devices because of their fast response times, wide viewing angles, and excellent contrasts. However, organic layers, including organic emission layers, can be moisture and oxygen sensitive, and thus, the life span of devices is seriously degraded when moisture and/or oxygen infiltrates into the display regions of the light emitting units.
In typical organic light emitting display apparatuses, the peripheries of a display region are encapsulated with a metal cap or an encapsulating substrate, and sealed thereto with a sealant. Furthermore, some embodiments comprise a moisture absorbent within the sealed space. However, these methods do not sufficiently block external oxygen or moisture in many cases.